Cold welding of metal



May 26, 1953 A. B. SOWTER 2,639,633

- cow WELDING OF METAL Filed Aug. '7, 1948 2 Sheets-Sheet 1 (Q 2 LL i INVENTOR ANTHONY 46N011 f w BY kQ-iaW y 6,- 953 A. B. SOWTER 2,639,633

COLD WELDING 0F METAL Filed Aug. 7, 1948 2 Sheets-Sheet 2 mve'NroR I AN HONY BMW/01.1 SON/76R BY N. s ATrozrvzY Patented May 26, 1953 COLD WELDING OF METAL Anthony Bagnold Sowter, Wembley, England, assignor to The General Electric Company, Limited, London, England Application August 7, 1948, Serial No. 43,096 In Great Britain April 24, 1947 2 Claims.

This invention relates to the cold welding of metal such as aluminium, aluminium alloys, copper etc.

It is well known that surfaces of certain metals can be cold welded together to produce an hermetic seal and one of the objects of the present invention is the provision of a method of and apparatus for cold welding the seam. of an aluminium sheath for an electric cable.

According to one aspect of the present invention, a method of welding together the contacting surfaces of two metallic strips, flanges or the like capable of being cold welded comprises applying pressure with a tool to produce a cold weld with only a percentage reduction in thickness of the two strips, flanges or the like, the surface of the tool in the direction of flow of metal or welding being substantially flat. Laterally of the said line, shearing or parting off excess metal may be effected.

Extensions or parts of the cooperating tools which produce the cold weld may shear or part off the excess metal or, alternatively, separate shearing or parting tools may be used.

According to another aspect of the invention, apparatus for welding together the contacting surfaces of two strips, flanges or the like of metal capable of being cold welded, comprises first tool means arranged to produce along one line a cold weld with only a percentage reduction in thickness of the two strips, flanges or the like and second tool means arranged to shear or part off excess metal laterally of the said line. The first and second tool means may be combined in a single pair of cooperating tools.

Thus, the apparatus may comprise a pair of pressure rolls through which two strips or flanges are fed and the pressure surfaces of the rolls may be such that they produce both a cold weld and a shear. The said surfaces may be flanged somewhat in the form of railway wheels, the flanges producing shearing or parting ofi.

Apparatus for cold welding the seam of an aluminium sheath of a single core electric cable and in accordance with the present invention will now be described by way of example with reference to the accompanying drawings in which Figure 1 shows a side elevation, partly in section, of the apparatus, Figure 2 shows a plan view of the apparatus, some parts being omitted and others broken away for clarity, Figure 3 shows a section on the line III-III in Figure 1, Figure 4 shows, in detail, the forming edge of the pair of pressure rolls in the apparatus, Figure 5 shows the shape of the aluminium strip used for sheathing the cable after it has passed through the first set of rolls of the apparatus, Figure 6 shows the strip shape after it has passed through the second set of rolls and contains the single electric conductor, Figure '7 shows the cable as it is operated on by the cold welding or pressure rolls and Figure 8 shows a similar view of the cable as it would appear if no shearing or parting oif edges were provided on the pressure rolls.

Referring now to the drawings and, more particularly, Figures 1-4 thereof, the apparatus comprises a steel base plate I on which all the various rolls are mounted and these rolls comprise a first pair of rolls 2, a. second pair 3, a pair of cold welding or pressure rolls 4, a pair of finishing rolls 5 and two pairs of guiding rolls 6 and I. A feed wheel 8 is mounted adjustably on a pillar 9 for guiding the electric conductor (not shown) into the aluminium sheath, this feed wheel 8 being placed between the first and second pairs of rolls 2 and 3 adjacent the set 3. A rotating scratch brush I0 is also provided between t'he pairs of rolls 2 and 3 for cleaning the edges: of the aluminium strip to: be cold welded together and this is driven by an independent electric motor (not shown).

'Only the cold welding rolls 4 are arranged to be driven, these rolls 4 drawing or forcing the aluminium sheath through the other rolls, and, for this purpose, a horizontal cross shaft II is provided. This drives a worm gear [2 meshing with a gear wheel I3 on the bottom of a vertical shaft I4 carrying one roll 4, the roll 4 being keyed to the shaft I4, and the shaft I5 of the other roll 4 is driven through a gear wheel I6 on the shaft I5 meshing with a gear wheel I! on the shaft I4. The shaft II is arranged to be driven in any suitable manner, for example, it may be driven from an electric motor by way of pulleys and belt drive, one pulley being mounted on the shaft I I.

The rolls of each of pairs of rolls 3 and 4 are not exactly identical since it will be seen that one roll 3 is provided with a fiat flange I8 which runs under the other roll 3 whilst one roll 4 is provided with a flat flange I9 which runs under the other roll 4. These flanges I8 and I9 back up the lower edges of the forming portions of the rolls.

The forming portions of the rolls 4 can be seen better from Figure 4 and it will be seen that each roll has a semi-circular portion 20, a flat cold welding portion 2I and a projecting portion or flange 22, the flanges of the two rolls almost meeting. The portions 22 effect the shearing or parting off of excess metal flowing and displaced laterally as a result of the cold weld and, if desired, they may actually meet.

The operation of the apparatus is as follows. Aluminium strip of the correct width and thickness is fed first through the rolls 2 whose cooperating surfaces are so shaped as to produce a strip section as shown in Figure 5. Then the strip is passed under the rotating scratch brush l which cleans the edges of the flanges 23 of the strip 24 to ensure a good cold weld. The, next step is to feed the electric conductor into' the strip and this is done by the wh'eeli 8. The strip 24 now moves between the rolls 3: and thesemoll'ss 3 force up the flan es 23 of the strip 24 and when it leaves the rolls 3, its section is as shown in Figure 6.

The strip 24 is now ready for the cold welding and shearing operation and passes to the rolls 4 which press the flanges 23. together with suflicient pressureto cause the metal of the flanges to flow laterall of the 2" dtherehytocold weld ingof the; metal at. the. weld due to the coldpres sureworl-Ling during the-welding operation, strain or work hardening of this typeresulting from any kind of cold working of metal: being a commonly known fact in the art.

Referring now to-Pigure- 7, as thestripv 2-4 moves past the cold welding and shearing line 25, so a cold weld.- 29 is produced and the excess metal 21 is sheared off and curls away. By providing the projecting portions 22-. on the rolls i, better welding'and sealing'is produced than if'flat rolls were used; shearing automatically even without 100% reductionin thickness of the metal between the pressure rolls and where. this self -parting or selflshea-ring occurs as is indicated somewhat. diagramat-ically in- Figure 8, there isa tendency: for tears to run: through the weld.

If desired, when the seam of the: cable sheath has been welded as describedabove,-.the seam may be turned over into the main' cable sheath or otherwise treated to reduce the projecting size thereof. It is, for example, possible tov increase the thickness or metal at or near the weld by a swaging process, which the seamis driven back towards'thecentre of the cable.

Forthispurpcs-e, a roller maybe provided situated on the outlet side of the pressure rolls 4, the roller having its axis horizontal and being of tapering or fi'usto-conical shape so that the weldis'bent or set over at an angle as itengages-the rollefssur-face. Thereafter, a further set ofrolls aluminium strip, the flanges2-ft of the-strip. 2.4.

may be of increased thickness or. the edgesmay Actually flat rolls sometimes produce be turned over to double the thickness of metal.

In the apparatus as described above, the axes of the rolls 4 are at right angles to the length of the strip 24 of aluminium as it passes through the rolls 3 and 4 and the excess metal 21 curls away to one side. The strip width and size is relatively small and the excess metal 21 has litte strength and can move in 'this fashion but where larger cable sheathing is being made, it is sometimes advisable to turn the axes of the pressure rolls. at a. suitable angle other than to the length of the aluminium strip so that, in effect, the welded sheath leaves the rolls at an angle other than 90'to the axes of the rolls whilst the excess" metalleaves at an angle of 90 to the roll axes. This ensures that excess metal sheared 01f cannotafl'ectthe cold welded scam.

I claim:

1.. Apparatus for welding together outwardlyextending flanges of a pre-I'ormed circular-bent metal. strip comprising apair of pressure rolls, said. rolls including cooperating opposed peripheral grooves to receive the circular-bent strip, intermediate cooperating peripheral portions adjacent the grooves to engage and apply welding pressure to the outside surfaces of said outwardly=-extending flanges, and cooperating outi zardly-eiztending perlpheralshearing edgespositioned at the sideof sa-idpressure-applying portions: remotes from said grooves, to shear of. the outer edge portions of said flanges substantially simultaneously with thewelding of the flanges together;

2. Apparatus as defined in claim 1 in which one of pressure rollshas an outwardly-extending flange which underlies. the other pressure, roll.

ANTHONY BAGNOLD SOWTER.

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